Researchers have provided early evidence to suggest that a blood test could be used to identify patients with colorectal cancer who may benefit from more intensive chemotherapy. Their study was published in Clinical Colorectal Cancer (2015; doi:10.1016/j.clcc.2014.12.006).
Colorectal, or bowel, cancer is the third biggest cancer killer in the United States. It is most commonly treated with a combination of chemotherapy agents, and outcomes can be improved by using additional drugs. However, this multidrug approach can increase side effects such as hair loss, low white blood cell count, diarrhea, and damage to the peripheral nervous system.
The research team counted tumor cells in a patient’s blood sample as a way of predicting who might benefit most.
“We are interested in detecting cancer cells that have been shed from a patient’s tumor and are circulating in their blood. In this study we wanted to see if the number of tumor cells in a blood sample could be linked to how well patients respond to intensive chemotherapy,” said study co-leader Professor Caroline Dive, PhD, from the Cancer Research UK Manchester Institute at The University of Manchester, which is part of the Manchester Cancer Research Centre in the United Kingdom.
The group looked at patients with advanced colorectal cancer who received a four-drug combination treatment. They confirmed that those patients with three or more circulating tumor cells (CTCs) in their blood sample had a lower overall survival, compared with those patients who had fewer than three CTCs. The team also presented data that suggested that patients with a higher CTC count before treatment could benefit more from this more intensive treatment regimen.
“Our initial results suggest that this test could prove useful for patient selection and we should now validate it in further larger trials of new treatments for bowel cancer,” said study co-leader Mark Saunders, MD, a consultant oncologist from The Christie NHS Foundation Trust.
The researchers also commented that these studies are important for developing a more personalized treatment approach. This will allow patients to receive the treatments that are most likely to benefit them.